21004089408 has 84 divisors (see below), whose sum is σ = 60231101788. Its totient is φ = 6998261760.

The previous prime is 21004089397. The next prime is 21004089409. The reversal of 21004089408 is 80498040012.

It can be written as a sum of positive squares in 2 ways, for example, as 13254456384 + 7749633024 = 115128^2 + 88032^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21004089409) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1555968 + ... + 1569408.

Almost surely, 2^21004089408 is an apocalyptic number.

It is an amenable number.

21004089408 is an abundant number, since it is smaller than the sum of its proper divisors (39227012380).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21004089408 is a wasteful number, since it uses less digits than its factorization.

21004089408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16172 (or 16159 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The spelling of 21004089408 in words is "twenty-one billion, four million, eighty-nine thousand, four hundred eight".